A source explained: "The X Factor no longer has a monopoly on the Christmas No1 like in the early days, so this exciting spin on the winner’s single will ensure it is in the running. James, Leona and the Kaiser Chiefs are friends of the show and were happy to lend their vocals to the winner’s singles, even though only one of the records will see the light of day.

“While Dalton, Anthony or Scarlett have to share the glory, the chance to collaborate with one of the country’s biggest acts on their first ever release is an added perk.”

It's not the first winner's song to feature a duet - last year's champs Rak-Su released their winner's single Dimelo together with Wyclef Jean and Naughty Boy.